Production of profiled sections from sheet metal by rolling



b 7, 9-; E. PENKALA 7 ,1

rnoaucnou OF PROFILED sE'JTIo'Ns FROM SHEET METAL BY ROLLING Filed June19, 1937 Patented Feb. 7, 1939 PATENT OFFICE V 2,146,223 PRODUCTION OFPROFILEDI -sEc'rIoNs FROMSHEET METAL BY- ROLLING.

Emil Penkalag liondon, England, assignor to Metal Trim Limited,.fLondon,England, a British com-,-

ApplicationJune 1'9, 1937,-Serial;No.' 149,217.. In .Great Britain June29, 1936,

2 Claims.

This invention relates to the production of profiled sections and-tubesby rolling from sheet metal, andhas among its objects to obviate or toreduce to a minimum stretching of the ma- 5 terial in the longitudinal.direction, for instance at theedges or marginal partsof .the section,whichstretchingis liable to result in theformation of waves orcorrugations which are difficult to eliminate in subsequent operations,to reduce to aminimumllateral. stretching of thematerial and. consequentfurther thinningof the same atthe corners or bent parts of the section,and generally to enableprofiled sections to be produced .with acomparatively low rolling pressure 5 wherebylthe size of the rollers,diameter of the spindles: carrying the :same, and the power employedmaybe very substantially reduced.

In themethod usually employed for the production of profiled sectionsbyrolling from sheet metal, therollers of each pass are profiled so as tocorrespond exactlyto the profile of the section at .theparticularposition. It has, however, been proposed to profile the rollers so thatthe materialis gripped by the, rollers at or adjacenttheedges ormarginal parts of the section andcis: left substantially free at thecorner or bend. :In this. prior proposal the application of thepressureat the edges or marginal parts would tend to increase the usuallongitudinal stretching action. It has also been proposed to profile therollers in such maner that the pressure is confined .to the corner orbent portion of the section. In such an arrangement pressure onthelongitudinally stretched parts is avoided, but inasmuch as the pressureis concentrated on ,the laterally stretched parts at the bend or corner,such lateral stretching, with.its accompanying thinning of the metal,would be increased.

According to the present invention the profiled sections are produced byrolling from sheet metal by passing the metal between rollers which ,areprofiled so that the pressure of the rollers onthe material is confinedto intermediate parts of the section which are not stretched. or subjectto stretching during the profiling operations. More specifically, theinvention embraces a method wherein the rolling. pressure is applied :atand confined to parts of thesection at which there is no, orsubstantially no, tendency. to 1on- I gitudinal or lateral stretching,the pressure preferablynbeing confined to positions adjacentthe bendorbends in the section, but not at such bend or bends. Thus, no part. ofthe: section liable to stretching, either longitudinally or lat- 955erally lvis.subjecttito pressure which would tend also is lower.-

to increase such stretching;withg,itsaccompany ing thinningof the metal.

In order to eliminate any groovingor line marking of the section by theapplication of the localized pressure according to the invention, and 5also to ensure true rolling of the section Walls or flanks, the regionsof pressure in successive passes are arranged at different positions inthe walls or flanks of the section so as to overlap. Thus, any groovesor lines resulting from the .10 localized pressure in one pass will beeliminated in a succeeding pass.

Preferably. each;pasS,.i. e., each individual profile formation orstage, is duplicated or multiplied so that while the material is in anyone forma 15 tion or stage of formation it is subject to at least tworolling pressures localized at different overlapping parts of thesection wall .or walls. A further and important advantage of applyingthe pressure 'in overlapping stages as described is that true trollingof the desiredprofile can be effected with a very much lower rollingpressure than was heretofore possible and thus the rollers and theirspindles may be of lighter construction and the power required foroperation 1 The invention is hereinafter described by way of examplewith, reference to the accompanying diagrammatic drawing, in whichFigure 1 is a cross-sectionalview showing one stage in the formation ofan L section by the method according to the invention and illustratingthe manner in which the rollers preferably are profiled for thispurpose;

Figures 2 to 4 are similar views illustrating stages in the formation of.a U or tubularsection; and I Figures 5 to 8 are similar viewsillustrating successive stages in the formation of a U or channelsection according to a modification of the aforesaid method.

In carryingthe invention into effect according to one embodiment andwithreference more particularly to Figure 1 of the accompanying diagrammaticdrawing, the metal strip 1 is passed between the profiled rollers 2, 3by which it is upper roller 2 is shaped sothat the roller profiles atthe-parts between which the walls orfianlgs of the sectioncare.disposed; are non-parallel :and 5-55 diverge as indicated by the anglea: degrees in a direction away from the bend in the strip. Thus, nopressure is applied at the edges of the strip. The lower roller 3 isformed with a circumferential groove or recess 3a so as to avoid anyapplication of pressure at or immediately adjacent the bend in thestrip.

In Figure 1 the rolling pressure is localized substantially at the partsa of the metal strip. This localized pressure not only avoids anyintensification of longitudinal stretching at the edges of the stripduring the profiling operation, but tends to compensate for any suchstretching that may occur, inasmuch as the localized pressure actingnear the bend in the section tends to cause a certain amount ofelongation of the metal strip at the bend and by suitable design of therollers any stretching at the edges may be neutralized entirely by thesaid elongation at the bend. Furthermore, as the inclined faces of theupper roll 2 act in a downward direction on the strip, the localizedpressure tends to upset the metal towards the bend and thus neutralizesany tendency to thinning of the metal at this point.

As shown in Figures 2 to 4, a U or tubular section is produced bypassing between successive pairs of rollers 4, 5, 6, 1 and 8, 9, theupper roller in each case being shaped similarly to the roller 2 inFigure 1 so that the pressure on the section is localized at the partsa.

The application of localized pressure in the manner described renders itpossible to produce profiled sections with a very much lower rollingpressure than was heretofore possible, but such localized pressuresometimes results in the formation of slight grooving Or line-marking ofthe section. In order to overcome such grooving or line-marking, whileat the same time retaining the advantages resulting from the use of acomparatively low rolling pressure, the localized pressure is insuccessive passes exerted or laterally displaced and overlappingportions of the metal stri A shown in Figure 5, which illustrates afirst stage in the formation, for example, of a U or channelled section,the upper roller I0 is shaped on the inclined sides so that the pressureon the walls or fianks of the section la is localized at the parts a asbefore described. The roller I0 is formed with a centrally disposedcircumferential groove or recess Illa so that the pressure on thecentral portion of the section is localized at the parts a The sameresult may be secured by providing a centrally disposed circumferentialgroove or recess Ila in the lower roller H or, if desired, both rollersmay be provided with the grooves.

In the next pass, as shown in Figure 6, the upper roller I2 is formedwith two circumferential grooves or recesses |2a each of which is ofless width than the width of the pressure region a in Figure 5 so thatthe pressure on the central portion of the section is localized at thepart a which overlaps the parts a in the preceding pass. The lowerroller l3 likewise may be provided with circumferential grooves orrecesses Hot, in which case the grooves I2a may be dispensed with.

In the next pass, as shown in Figure '7, the upper roller I4 is formedwith a centrally disposed circumferential groove or recess la the widthof which is less than the width of the pressure region a. in Figure 6,whereby the rolling pressure on the central portion of the section islocalized at the parts a which overlap the part a in the preceding pass.If desired, the lower roller ii in this pass also may be formed with acentrally disposed groove or recess corresponding to the groove orrecess l4a.

In the final pass, as shown in Figure 8, the rollers [6, ll may beprofiled to correspond to the final profile of the section la.

Preferably all the upper rollers are relieved in the manner describedwith reference to Figure 1 so that the pressure on the section walls orflanks is applied at the parts a adjacent the bend or corner. Ifdesired, however, the upper rollers may be relieved in any othersuitable manner for the same purpose.

The application of the localized pressure in overlapping stages asdescribed with reference to Figures 5 to 8, in addition to eliminatinglinemarking or grooving, also facilitates upsetting of the metal into ortowards the corner or bend in the section. to compensate for the naturalthinning tendency due to the lateral stretching. Obviously, by applyingthe localized pressure in overlapping stages the metal may be upsettowards the bend or corner with a comparatively low pressure on therollers, and such upsetting may serve to increase the thickness of thesection at the bend or corner.

The invention may be carried into effect by the use of rollers suitablyrelieved or recessed to avoid the application of pressure at any partssubject to stretching or which have been stretched longitudinally orlaterally, or rollers in accordance with my copending application SerialNumber 149,219, filed June 19, 1937, advantageously are employed, itbeing understood that although a slight relieving of the rollers issufificient for the purpose, recesses of substantial depth arepermissible.

The invention, while being of general application in the rolling ofprofiled sections from sheet metal, is particularly applicable for usein connection with the rolling method and apparatus according to myprior application Serial Number 149,216, filed June 19, 1937, andaccording to my further co-pending applications Serial Numbers 149,218and 149,220, both filed June 19, 1937.

What I claim and desire to secure by Letters Patent is:

1. A method for the production of profiled sections from sheet metal bybending the metal along one or more longitudinal lines, in such mannerthat there is a tendency for the metal to stretch laterally in one ormore zones containing the lines of bend and to stretch longitudinally inzones laterally remote from said lines, with substantially no tendencyto stretch in any direction in neutral zones of substantial area locatedbetween the first mentioned and second mentioned zones, said methodcomprising the application of rolling pressure exclusively to saidneutral zones by squeezing the metal of said neutral zones in sufiicientdegree to cause a slight thinning thereof.

2. The method set forth in claim 1, char- EMIL PENKALA.

I CERTIFICATE OF CORRECTION, Patent No. 2, 114.6,225 February 7, 1959.

EMIL PENKALA.

It is hereby certified that the above numbered patent was erroneously hissued to "Metal Trim Limited" as assignee of the entire interesttherein whereas said patent should have been issued to -Emil Penkala, ofLondon, England, assign'or of one-half interest to Metal Trim Limited,of London, England, a British company-- as shown by the record ofassignments in this office; and that the said Letters Patent should beread with this correction merein that the same may conform to the recordofthe case in the Patent Office.

Signed and sealed this 9th day of October, A. D. 1915.

Leslie Frazer (Seal) First Assistant Commissioner of Patents

